In-Situ Upgrading Of Biomass Pyrolysis Vapor Using Water-Gas Shift And Hydroprocessing

ABSTRACT

Processes for thermal conversion of biomass are provided. The processes involve upgrading the pyrolysis vapor from a pyrolysis reactor. The steps include thermally converting a biomass feedstock in a pyrolysis reactor, recovering a pyrolysis vapor from the reactor, passing the pyrolysis vapor in contact with a water-gas shift reaction catalyst and a hydrotreating catalyst, and converting the resulting upgraded pyrolysis vapor into a liquid product. The resulting biooil liquid product is more refined, and the overall processes offer economic and energy efficiency.

TECHNICAL FIELD

The present application relates to a process of upgrading biomasspyrolysis vapor. More specifically, the present application relates to aprocess of in-situ upgrading of biomass pyrolysis vapor using amulti-layer catalyst bed or a cascade of catalytic reactors.

BACKGROUND

With the diminishing supply of fossil fuels, the use of renewable energysources is becoming increasingly important as a feedstock for productionof hydrocarbon compounds. Thermal conversion of carbonaceous materials,such as biomass and waste, can play an important role to providematerials that can replace fossil fuels. These conversions can beaccomplished by pyrolysis processes.

Pyrolysis is one of two major pathways for converting biomass into fuelsor chemicals in a thermochemical platform. The major product from acommon fast pyrolysis process is called biocrude or biooil, a dark brownliquid that generally is acidic and has high oxygen and water content,which are characteristics that are usually not favored by existingrefinery equipment or processes used for further processing totransportation fuels. For instance, the oxygen content could be 50weight percent (wt %) or higher in biooil, thus requiring a high amountof hydrogen to upgrade the biooil into hydrocarbon fuels viahydroprocessing, which makes the process economically unattractive. Inaddition, the acidity of biooil causes the biooil to be corrosive toexisting pipelines. Moreover, the water content is typically 20 to 30 wt% and the biooil is immiscible with petroleum crude, which makesco-refining difficult. Therefore, biooils with improved properties, suchas with less oxygen, less water, and close to neutral pH, would bepreferred.

Currently, most research on improving the properties of biooil has beenfocused on post-pyrolysis treatment involving upgrading the liquidbiooil obtained from fast pyrolysis with hydroprocessing orhydrotreating, and other reactions like esterification. However, littleor no effort has been put into in situ catalytic upgrading of pyrolysisvapor before it is condensed into liquid. For example, one common biooilupgrading method is to first separate it into two phases (aqueous andlignin phase), and then use the pyrolytic lignin phase (or organicphase) for hydroprocessing, while the aqueous phase is passed ontosteam-reforming to generate the hydrogen required by thehydroprocessing. Although this approach may work, one distinctdisadvantage is that both the aqueous and lignin phases have to bereheated up to high temperatures for steam reforming andhydroprocessing, which would require extra heat or energy, thusconsiderably reducing the overall thermal efficiency of the process.

Biomass-derived pyrolysis oil has the potential to replace up to 60percent (%) of transportation fuels, thereby reducing the dependency onconventional petroleum and reducing its environmental impact. Therefore,there is a need in the industry for a process that is more economicaland energy efficient for converting biomass to fuels.

SUMMARY

The present invention provides a process for in-situ upgrading ofbiomass pyrolysis vapor using a multi-layered catalyst bed or cascadedcatalytic reactors. In one aspect, the present process for the thermalconversion of biomass comprises the steps of a) thermal conversion of abiomass feedstock in a pyrolysis reactor, b) recovering a pyrolysisvapor from the reactor, c) passing the pyrolysis vapor in contact with acracking catalyst, a water-gas shift reaction catalyst, a hydrotreatingcatalyst, and an acid catalyst, and d) converting the resultingpyrolysis vapor from step c) into a liquid product.

In one other aspect, the present process for the thermal conversion ofbiomass comprises the steps of a) thermal conversion of a biomassfeedstock in a pyrolysis reactor, b) recovering a pyrolysis vapor fromthe reactor, c) passing the pyrolysis vapor in contact with an acidcatalyst in the presence of an alcohol, and d) converting the resultingpyrolysis vapor from step c) into a liquid product.

In another aspect, the present process for the thermal conversion ofbiomass comprises the steps of a) thermal conversion of a biomassfeedstock in a pyrolysis reactor, b) recovering a pyrolysis vapor fromthe reactor, c) passing the pyrolysis vapor in contact with a water-gasshift reaction catalyst and a hydrotreating catalyst, and d) convertingthe resulting pyrolysis vapor from step c) into a liquid product.

In yet another aspect, the present process for the thermal conversion ofbiomass comprises the steps of a) thermal conversion of a biomassfeedstock in a pyrolysis reactor, b) recovering a pyrolysis vapor fromthe reactor, c) passing the pyrolysis vapor in contact with a crackingcatalyst, a water-gas shift reaction catalyst, and a hydrotreatingcatalyst, and d) converting the resulting pyrolysis vapor from step c)into a liquid product.

Among other factors, it has been found that by in-situ upgrading thebiomass pyrolysis vapor using the series of catalysts of the presentprocesses, a liquid biooil product is obtained that is so refined thatthe liquid product can be combined with crude oil to make gasoline. Inaddition, it has been found that by in-situ upgrading the biomasspyrolysis vapor to have less acidity, one can attain a liquid biooilproduct which is easier to handle and less corrosive in post-pyrolysistreatment. It has also been found that in-situ upgrading of hotpyrolysis vapor is more attractive and economical, as biooil withimproved properties, such as less oxygen and/or less acidity, isproduced directly. This makes the further upgrading into liquidtransportation fuels more cost effective due to less hydrogen beingrequired. Energy is also saved for pyrolysis vapor cooling and pyrolysisoil reheating.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the exemplary embodiments of thepresent invention and the advantages thereof, reference is now made tothe following description in conjunction with the accompanying drawings,which are briefly described as follows.

FIG. 1 is a schematic of a process for in-situ upgrading of pyrolysisvapor using a multi-layered catalyst bed, with multiple layers of thedifferent catalysts, according to an exemplary embodiment.

FIG. 2 is a schematic of a process for in-situ upgrading of pyrolysisvapor using cascaded catalyst reactors (or beds), according to anexemplary embodiment.

FIG. 3 is a schematic of a process for in-situ upgrading of pyrolysisvapor using an acid catalyst in the presence of alcohol, according to anexemplary embodiment.

FIG. 4 is a schematic of a process for in-situ upgrading of pyrolysisvapor using a water-gas shift reaction catalyst and a hydrotreatingcatalyst, with multiple layers of the different catalysts, according toan exemplary embodiment.

FIG. 5 is a schematic of a process for in-situ upgrading of pyrolysisvapor using a water-gas shift reaction catalyst and a hydrotreatingcatalyst, using cascaded catalyst reactors (or beds), according to anexemplary embodiment.

FIG. 6 is a schematic of a process for in-situ upgrading of pyrolysisvapor using a cracking catalyst, a water-gas shift reaction catalyst,and a hydrotreating catalyst, with multiple layers of the differentcatalysts, according to an exemplary embodiment.

FIG. 7 is a schematic of a process for in-situ upgrading of pyrolysisvapor using a cracking catalyst, a water-gas shift reaction catalyst,and a hydrotreating catalyst, using cascaded catalyst reactors (orbeds), according to an exemplary embodiment.

DETAILED DESCRIPTION

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. One of ordinary skill in the art willappreciate that in the development of any such actual embodiment,numerous implementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present invention may be better understood by reading the followingdescription of non-limitative embodiments with reference to the attacheddrawings wherein like parts of each of the figures are identified by thesame reference characters. The words and phrases used herein should beunderstood and interpreted to have a meaning consistent with theunderstanding of those words and phrases by those skilled in therelevant art. No special definition of a term or phrase, for example, adefinition that is different from the ordinary and customary meaning asunderstood by those skilled in the art, is intended to be implied byconsistent usage of the term or phrase herein. To the extent that a termor phrase is intended to have a special meaning, for example, a meaningother than that understood by skilled artisans, such a specialdefinition will be expressly set forth in the specification in adefinitional manner that directly and unequivocally provides the specialdefinition for the term or phrase. Moreover, various streams orconditions may be referred to with terms such as “hot,” “cold,” “cooled,“warm,” etc., or other like terminology. Those skilled in the art willrecognize that such terms reflect conditions relative to another processstream, not an absolute measurement of any particular temperature.

The present application is directed to an improved biomass pyrolysisprocess that performs in-situ upgrading of pyrolysis-vapor usingdifferent catalysts. Specifically, a catalyst bed with multi-layeredcatalysts or cascaded catalytic reactors with different catalysts areimplemented in a regular fast pyrolysis unit. The biooil produced thisway will have improved properties, for instance, lower oxygen contentand/or less acidity, over biooils produced from regular fast pyrolysis.The present application is also directed to systems for implementingsuch processes.

Referring to FIG. 1, a process 100 for in-situ upgrading of pyrolysisvapor using a multi-layered catalyst bed reactor 102 is illustrated. Abiomass stream 104 and a recycled off-gas stream 106 are fed into afluid bed pyrolysis reactor 108. In certain exemplary embodiments, therecycled off-gas stream 106 includes nitrogen (N₂). The recycled off gasstream 106 fluidizes the bed in the pyrolysis reactor 108. In certainexemplary embodiments, the biomass stream 104 includes wood sawdust,bark, yard waste, waste lumber, agricultural wastes, peat, paper millwastes, cellulosic wastes, municipal solid waste, food processingwastes, sewage sludge, and the like. In certain embodiments, the biomassstream 104 can be dried prior to entering the fluid bed pyrolysisreactor 108. In certain exemplary embodiments, the biomass stream 104 isdried to less than 10 wt % moisture content. In certain exemplaryembodiments, the biomass stream 104 is ground to form small particles,for instance, less than 3 millimeters (mm) in its shortest dimension.

The pyrolysis reactor 108 is any reactor type capable of completing apyrolysis reaction involving thermal decomposition of the biomass stream104 at short reaction times. The pyrolysis reaction is sometimes called“fast”, “flash”, or “rapid” pyrolysis. The reaction is conducted in areactor type capable of high heat transfer rates to small biomassparticles, in order to achieve the rapid increase in temperature of theparticle that is necessary. Suitable examples of pyrolysis reactorsinclude, but are not limited to, fluidized bed reactors, circulatingfluidized bed reactors, and transport reactors. In fluidized bedreactors and circulating fluidized bed reactors, hot gases and solidsare brought into intimate contact with the biomass particles in thebiomass stream 104. In certain exemplary embodiments, the solids arenormally inert, for instance, silica or sand. In transport reactors,either hot gas alone or a mixture of hot gas and solids may be used. Allreactors generally require a significant recycled off-gas flow, usuallyfrom about 1 to about 10 times the weight of biomass stream 104 beingprocessed. If the pyrolysis reaction is carried out in the absence ofoxygen, for example, in a nitrogen atmosphere, then the non-condensablegases formed have significant contents of carbon monoxide, hydrogen,methane and other light hydrocarbons or organics, which can be burned.The pyrolysis reactor 108 is generally operated at conditions whichpromote maximum yield of organic liquid. In certain exemplaryembodiments, the pyrolysis reactor 108 is operated at a temperature inthe range of from about 400 degrees Celsius (° C.) to about 650° C., avapor residence time of less than about 2 seconds, and at substantiallyatmospheric pressure. Generally, the pyrolysis reaction yields apyrolysis vapor stream 110 that exits a top 108 a of the pyrolysisreactor 108.

Once the pyrolysis on the biomass stream 104 is complete, the pyrolysisvapor stream 110 is often passed through separation devices, such asfilters or cyclones, in order to remove any entrained solid particles,or char, 112 a, 112 b, resulting from the pyrolysis reaction. In certainexemplary embodiments, the pyrolysis vapor stream 110 enters a firstcyclone reactor 114 to separate pyrolysis vapors from entrained char. Apyrolysis vapor stream 116 exits the first cyclone reactor 114 andenters a second cyclone reactor 118 to further separate pyrolysis vaporsfrom entrained char. A pyrolysis vapor stream 120 exits the secondcyclone reactor 118 and is introduced at a top 102 a of themulti-layered catalyst bed reactor 102. In certain exemplaryembodiments, the pyrolysis vapor stream 120 is substantially free ofparticles so as not to plug the catalyst bed reactor 102.

The catalyst bed reactor 102 includes multiple layers of the differentcatalysts. The pyrolysis vapor stream 120 passes through each catalystbed, in sequence from the top 102 a to a bottom 102 b, in themulti-layer catalyst bed reactor 102. The selection and propercombination of different catalysts is important, as it determines theperformance of the catalytic treatment of the pyrolysis vapor stream120.

In certain exemplary embodiments, a top catalyst 102 c would be azeolite type cracking catalyst, preferably HZSM-5, as this catalyst canbe operated at a temperature between about 370 and about 410° C., atatmospheric pressure. The cracking catalyst will crack the hydrocarbonin the pyrolysis vapor stream 120. Suitable examples of other zeolitecracking catalysts for use include, but are not limited to, REX, REY,and USY zeolites. Any suitable temperature and pressure can be used,based upon the degree of cracking desired. Some zeolite type catalysts,such HZSM-5, are prone to coke or char formation on the catalyst. Theextent of the coking can be controlled by the relative space velocity ofthe pyrolysis vapor stream in the catalyst bed. Other crackingcatalysts, for example those used in catalytic crackers (for instancefluid catalytic cracking units), may be less prone to coking relative tozeolites. Other types of catalysts, such as alumina based catalysts, canbe used as cracking catalysts and will have lower coking tendencies.

In certain exemplary embodiments, a middle catalyst 102 d would be ahigh temperature water-gas-shift catalyst, for example, a precious metalcatalyst such as platinum (Pt)/mixed oxide, which are good for operatingin the temperature range of from about 350 to about 450° C. The purposeof using a shift catalyst is to convert the water and carbon monoxide(CO) in the pyrolysis vapor stream 120 into hydrogen (H₂) and carbondioxide (CO₂), thus providing the hydrogen required byhydrodeoxygenation or hydrotreating. The water-gas shift reactioncatalysts generally include a transition metal or transition metaloxide. In certain exemplary embodiments, precious metal catalysts, suchas platinum in a mixed oxide, are utilized for operating in atemperature range of from about 350 to about 450° C. The hydrogen isthen available for the hydrotreating or hydrodeoxygenation. The relativespace velocity of the hot vapor stream through the bed can be designedand controlled to produce the maximum amount of hydrogen. The limitingfactor will be the amount of carbon monoxide present in the pyrolysisvapor stream. Since water-gas shift is an equilibrium process, injectionof additional hot water vapor before this catalyst would drive theconversion of all of the carbon monoxide into carbon dioxide and producemore hydrogen.

A third catalyst 102 e would include a hydrotreating (orhydrodeoxygenation) catalyst. Suitable examples of hydrotreating orhydrodeoxygenation catalysts include, but are not limited to, any knownnickel molybdenum (NiMo), cobalt molybdenum (CoMo), or noble metalcatalyst supported on γ-alumina. Generally, such catalysts arecommercially available. In certain exemplary embodiments, the reactionis generally run at a temperature in the range from about 350 to about450° C., at atmospheric pressure. The hydrotreating removes the oxygencontaining-hydrocarbons in the pyrolysis vapor.

In certain exemplary embodiments, a solid acid catalyst 102 f, such assulfated zirconia, zeolite β, or Nafion-silicone disoxide (SiO₂)composite (SAC-13), can be added to the very bottom 102 b of thecatalyst bed reactor 102 with an injection of an alcohol stream 124 toperform an esterification process. The alcohol stream 124 can includemethanol or ethanol, and can be injected into the catalyst 102 f bed,catalyst bed reactor 102, or pyrolysis vapor stream 120 to support theesterification reaction. The purpose of using the catalyst 102 f is toreduce the acidity of pyrolysis vapor stream 120 by letting thecarboxylic acid (e.g., acetic acid) in the pyrolysis vapor stream 120react with the alcohol stream 124 to form ester and water. An upgradedpyrolysis vapor stream 130 is removed from the bottom 102 b of thecatalyst bed reactor 102 and directed to a quench tower 134. Thepyrolysis vapor stream 130 is generally less acidic and safer fortransport through pipes and equipment.

The order in which the pyrolysis vapor stream 120 contacts the foregoingcatalysts can be any order. In certain exemplary embodiments, thewater-gas shift catalyst is generally contacted prior to thehydrotreating catalyst so that the water-gas shift reaction can producehydrogen, which can be used in the hydrotreating reaction, and therebymake the process more efficient. In one embodiment, the crackingcatalyst is contacted first, followed by the water-gas shift catalyst,hydrotreating catalyst, and then the acid catalyst. In anotherembodiment, the water-gas shift catalyst is contacted first, followed bythe hydrotreating catalyst, the acid catalyst, and then the crackingcatalyst.

The pyrolysis vapor stream 130 is quenched and converted into a liquidbiooil product 140, and collected at a base 136 of the quench tower 134.A portion 140 a of the biooil product 140 is collected in a biooilcollection tank 144, while a portion 140 b can be pumped via pump 146through a heat exchanger 148 to produce a cooled biooil stream 150. Incertain exemplary embodiments, the cooled biooil stream 150 isreintroduced at a top 134 a of the quench tower 134 to quench thepyrolysis vapor stream 130.

In certain exemplary embodiments, a biooil vapor stream 154 from thequench tower 134 is directed to a condenser 156 to cool and condense thebiooil vapor stream 154 to produce a condensed biooil stream 158 and anon-condensable gas stream 160. In certain exemplary embodiments, thecondensed biooil stream 158 is routed to the biooil collection tank 144.The biooil collected in tank 144 generally has an oxygen content in therange of from about 30 to about 40 percent (%) (dry, ash free basis) anda water content in the range of from about 15 to about 25%, depending onthe operating temperatures of the quench tower and the condensers. Thebiooil product is generally phase stable and which may separate from alighter density, more water rich product phase. Typical pH values forthe biooil product are in the range of from about 2 to about 5.

FIG. 2 illustrates a process 200 for in-situ upgrading of pyrolysisvapor, according to another exemplary embodiment. The process 200 forin-situ upgrading of pyrolysis vapor is the same as that described abovewith regard to the process 100 for in-situ upgrading of pyrolysis vapor,except as specifically stated below. For the sake of brevity, thesimilarities will not be repeated hereinbelow. The process 200 utilizescascaded catalytic reactors, each having a single type of catalysttherein.

Referring now to FIG. 2, the pyrolysis vapor stream 120 free ofparticles exits the second cyclone reactor 118 and is passed through aheat exchanger 202 to control the temperature of the pyrolysis vaporstream 120 to produce a pyrolysis vapor stream 204. The temperature ofthe pyrolysis vapor stream 120 is adjusted to achieve optimal conditionsfor catalysis. The pyrolysis vapor stream 204 is introduced into a firstcatalytic reactor 208. In certain exemplary embodiments, the firstcatalytic reactor 208 includes a zeolite cracking catalyst therein. Apyrolysis vapor stream 210 exits the first catalytic reactor 208 and ispassed through a heat exchanger 212 to control the temperature of thepyrolysis vapor stream 210 to produce a pyrolysis vapor stream 214. Thetemperature of the pyrolysis vapor stream 210 is adjusted to achieveoptimal conditions for catalysis.

The pyrolysis vapor stream 214 is introduced into a second catalyticreactor 218. In certain exemplary embodiments, the second catalyticreactor 218 includes a water-gas shift catalyst therein. A pyrolysisvapor stream 220 exits the second catalytic reactor 218 and is passedthrough a heat exchanger 222 to control the temperature of the pyrolysisvapor stream 220 to produce a pyrolysis vapor stream 224. Thetemperature of the pyrolysis vapor stream 220 is adjusted to achieveoptimal conditions for catalysis.

The pyrolysis vapor stream 224 is introduced into a third catalyticreactor 228. In certain exemplary embodiments, the third catalyticreactor 228 includes a hydrotreating catalyst therein. A pyrolysis vaporstream 230 exits the third catalytic reactor 228 and is passed through aheat exchanger 232 to control the temperature of the pyrolysis vaporstream 230 to produce a pyrolysis vapor stream 234. The temperature ofthe pyrolysis vapor stream 230 is adjusted to achieve optimal conditionsfor catalysis.

The pyrolysis vapor stream 234 is introduced into a fourth catalyticreactor 238. In certain exemplary embodiments, the fourth catalyticreactor 238 includes an acid catalyst therein. The alcohol stream 124can be injected with the pyrolysis vapor stream 234 to perform theesterification process and lower the acidity of the resulting upgradedpyrolysis vapor stream 240. The pyrolysis vapor stream 240 exits thefourth catalytic reactor 238 and is directed to the quench tower 134.

Generally, the processes of the present invention involves thermalconversion of biomass by pyrolysis, i.e., in a pyrolysis reactor. Agreatly improved liquid, biooil product is obtained by the presentprocess as the pyrolysis vapor is upgraded. The pyrolysis vapor iscontacted with a cracking catalyst, a water-gas shift reaction catalyst,a hydrotreating catalyst and an acid catalyst. This particular selectionof catalysts provides an upgraded vapor that is converted into a liquidproduct by a means such as by quenching, thus resulting in a biooilliquid so refined that it can be combined with crude oil to give auseful gasoline product. No additional refining is necessary. Furtherrefining, of course, can be conducted to fine tune the properties of thebiooil product, depending on the ultimate product desired.

The selection and proper combination of the different catalysts allowsfor upgrading of the pyrolysis vapor, and thereby provides the resultingrefined biooil. The use of a cracking catalyst, in combination with ahydrotreating catalyst and a water-gas shift reaction catalyst, and anacid catalyst, can provide one with a liquid biooil product havingreduced oxygen and water content as well as lowered acidity. In general,the pyrolysis vapor can contact the different catalysts in any orderdesired. The catalysts can be arranged in a multi-layer fashion, inseparate reactors, or in a combination of such.

Contacting the catalysts with the pyrolysis vapor stream 120 can beconducted in any suitable fashion. In certain embodiments, thecontacting is conducted in a single reactor where the catalysts aresituated in a multilayer fashion. The vapor contacts each catalyst inorder as situated in the multilayer fashion. In other embodiments, thecatalysts are arranged in separate reactors, with the pyrolysis vaporbeing passed in sequence through each reactor. Heat exchangers can beincluded in between the cascaded reactors to heat or cool the pyrolysisvapor for the appropriate temperatures required by various upgradingcatalysts. In addition, it would allow for easier sampling of theupgraded vapor for analysis after each stage, thus allowing more controlover the process. In such an embodiment, the temperature and pressurefor each reaction can be better fine tuned to control the reaction.Also, guard beds can be placed before each reactor to filter outunwanted materials, if so desired.

FIG. 3 illustrates a process 300 for in-situ upgrading of pyrolysisvapor using the acid catalyst, according to an exemplary embodiment. Theprocess 300 for in-situ upgrading of pyrolysis vapor is the same as thatdescribed above with regard to the process 100 for in-situ upgrading ofpyrolysis vapor, except as specifically stated below. For the sake ofbrevity, the similarities will not be repeated hereinbelow. Referringnow to FIG. 3, the pyrolysis vapor stream 120 enters a catalyst bedreactor 302. The catalyst bed reactor 302 includes a solid acid catalystbed 302 f with an injection of alcohol stream 124 to perform anesterification process. An upgraded pyrolysis vapor stream 330 isremoved from a bottom 302 b of the catalyst bed reactor 302 and directedto the quench tower 134. The pyrolysis vapor stream 330 is generallyless acidic and safer for transport through pipes and equipment.

FIG. 4 illustrates a process 400 for in-situ upgrading of pyrolysisvapor using a water-gas shift catalyst and a hydrotreating (orhydrodeoxygenation) catalyst, according to an exemplary embodiment. Theprocess 400 for in-situ upgrading of pyrolysis vapor is the same as thatdescribed above with regard to the process 100 for in-situ upgrading ofpyrolysis vapor, except as specifically stated below. For the sake ofbrevity, the similarities will not be repeated hereinbelow. Referringnow to FIG. 4, the pyrolysis vapor stream 120 enters a catalyst bedreactor 402 having a top catalyst 402 d and a bottom catalyst 402 e. Thecatalyst bed reactor 402 includes multiple layers of the differentcatalysts. In certain exemplary embodiments, the top catalyst 402 d is awater-gas shift catalyst. In certain exemplary embodiments, the bottomcatalyst 402 e is a hydrotreating catalyst. The pyrolysis vapor stream120 passes through each catalyst bed, in sequence from a top 402 a to abottom 402 b, in the multi-layer catalyst bed reactor 402. In certainexemplary embodiments, the water-gas shift catalyst is contacted first,followed by the hydrotreating catalyst. An upgraded pyrolysis vaporstream 430 is removed from the bottom 402 b of the catalyst bed reactor402 and directed to the quench tower 134.

FIG. 5 illustrates a process 500 for in-situ upgrading of pyrolysisvapor, according to another exemplary embodiment. The process 500 forin-situ upgrading of pyrolysis vapor is the same as that described abovewith regard to the process 400 for in-situ upgrading of pyrolysis vapor,except as specifically stated below. For the sake of brevity, thesimilarities will not be repeated hereinbelow. The process 500 utilizescascaded catalytic reactors, each having a single type of catalysttherein.

Referring now to FIG. 5, the pyrolysis vapor stream 120 is passedthrough a heat exchanger 512 to control the temperature of the pyrolysisvapor stream 120 to produce a pyrolysis vapor stream 514. Thetemperature of the pyrolysis vapor stream 120 is adjusted to achieveoptimal conditions for catalysis. The pyrolysis vapor stream 514 isintroduced into a first catalytic reactor 518. In certain exemplaryembodiments, the first catalytic reactor 518 includes a water-gas shiftcatalyst therein. A pyrolysis vapor stream 520 exits the first catalyticreactor 518 and is passed through a heat exchanger 522 to control thetemperature of the pyrolysis vapor stream 520 to produce a pyrolysisvapor stream 524. The temperature of the pyrolysis vapor stream 520 isadjusted to achieve optimal conditions for catalysis.

The pyrolysis vapor stream 524 is introduced into a second catalyticreactor 528. In certain exemplary embodiments, the second catalyticreactor 528 includes a hydrotreating catalyst therein. A pyrolysis vaporstream 530 exits the second catalytic reactor 528 and is directed to thequench tower 134. By upgrading the pyrolysis vapor in accordance withthe processes 400, 500, the overall upgrading process is more thermallyefficient. The heat loss due to condensation of pyrolysis vapor and thereheating of biooil is avoided. Furthermore, no hydrogen is needed, ashydrogen can be provided internally by the water-gas-shift reaction. Inaddition, the biooil produced from the quench tower 134 would have alower oxygen content, lower water content, and lower acidity.

FIG. 6 illustrates a process 600 for in-situ upgrading of pyrolysisvapor using a cracking catalyst, a water-gas shift catalyst, and ahydrotreating (or hydrodeoxygenation) catalyst, according to anexemplary embodiment. The process 600 for in-situ upgrading of pyrolysisvapor is the same as that described above with regard to the process 100for in-situ upgrading of pyrolysis vapor, except as specifically statedbelow. For the sake of brevity, the similarities will not be repeatedhereinbelow. Referring now to FIG. 6, the pyrolysis vapor stream 120enters a catalyst bed reactor 602 having a top catalyst 602 c, a middlecatalyst 602 d, and a bottom catalyst 602 e. The catalyst bed reactor602 includes multiple layers of the different catalysts. In certainexemplary embodiments, the top catalyst 602 c is a cracking catalyst. Incertain exemplary embodiments, the middle catalyst 602 d is a water-gasshift catalyst. In certain exemplary embodiments, the bottom catalyst602 e is a hydrotreating catalyst. The pyrolysis vapor stream 120 passesthrough each catalyst bed, in sequence from a top 602 a to a bottom 602b, in the multi-layer catalyst bed reactor 602. The order in which thepyrolysis vapor stream 120 contacts the foregoing catalysts can be anyorder. In certain exemplary embodiments, the water-gas shift catalyst isgenerally contacted prior to the hydrotreating catalyst so that thewater-gas shift reaction can produce hydrogen, which can be used in thehydrotreating reaction, and thereby make the process more efficient. Inone embodiment, the cracking catalyst is contacted first, followed bythe water-gas shift catalyst, and then the hydrotreating catalyst. Inanother embodiment, the water-gas shift catalyst is contacted first,followed by the hydrotreating catalyst, and then the cracking catalyst.An upgraded pyrolysis vapor stream 630 is removed from the bottom 602 bof the catalyst bed reactor 602 and directed to the quench tower 134.

FIG. 7 illustrates a process 700 for in-situ upgrading of pyrolysisvapor, according to another exemplary embodiment. The process 700 forin-situ upgrading of pyrolysis vapor is the same as that described abovewith regard to the process 600 for in-situ upgrading of pyrolysis vapor,except as specifically stated below. For the sake of brevity, thesimilarities will not be repeated hereinbelow. The process 700 utilizescascaded catalytic reactors, each having a single type of catalysttherein.

Referring now to FIG. 7, the pyrolysis vapor stream 120 is passedthrough a heat exchanger 702 to control the temperature of the pyrolysisvapor stream 120 to produce a pyrolysis vapor stream 704. Thetemperature of the pyrolysis vapor stream 120 is adjusted to achieveoptimal conditions for catalysis. The pyrolysis vapor stream 704 isintroduced into a first catalytic reactor 708. In certain exemplaryembodiments, the first catalytic reactor 708 includes a zeolite crackingcatalyst therein. A pyrolysis vapor stream 710 exits the first catalyticreactor 708 and is passed through a heat exchanger 712 to control thetemperature of the pyrolysis vapor stream 710 to produce a pyrolysisvapor stream 714. The temperature of the pyrolysis vapor stream 710 isadjusted to achieve optimal conditions for catalysis.

The pyrolysis vapor stream 714 is introduced into a second catalyticreactor 718. In certain exemplary embodiments, the second catalyticreactor 718 includes a water-gas shift catalyst therein. A pyrolysisvapor stream 720 exits the second catalytic reactor 718 and is passedthrough a heat exchanger 722 to control the temperature of the pyrolysisvapor stream 720 to produce a pyrolysis vapor stream 724. Thetemperature of the pyrolysis vapor stream 720 is adjusted to achieveoptimal conditions for catalysis.

The pyrolysis vapor stream 724 is introduced into a third catalyticreactor 728. In certain exemplary embodiments, the third catalyticreactor 728 includes a hydrotreating catalyst therein. A pyrolysis vaporstream 730 exits the third catalytic reactor 728 and is directed to thequench tower 134. By upgrading the pyrolysis vapor in accordance withthe processes 600, 700, the overall upgrading process is more thermallyefficient. The heat loss due to condensation of pyrolysis vapor and thereheating of biooil is avoided. Also, a liquid biooil product isobtained that is refined such that the product can be combined withcrude oil to produce gasoline. Furthermore, no hydrogen is needed, ashydrogen can be provided internally by the water-gas-shift reaction. Inaddition, the biooil produced from the quench tower 134 would have alower oxygen content, lower water content, and lower acidity.

By upgrading pyrolysis vapor in accordance with the processes of thepresent invention, the overall upgrading process is more thermallyefficient than conventional processes. Heat loss due to condensation ofpyrolysis vapor and reheating of biooil is avoided. Furthermore, nohydrogen (H₂) is needed, as hydrogen can be provided internally by thewater-gas-shift reactions. In addition, the biooil produced from thequench tower has less oxygen, less water, and fewer acids than biooilsproduced using conventional processes, and therefore has an improvedquality over conventional biooils. By treating the pyrolysis vapor inaccordance with the present invention, a liquid biooil product can beobtained that is already so refined that it can be combined directly, orwith minimal further refining, to crude oil to make a gasoline product.

To facilitate a better understanding of the present invention, thefollowing examples of certain aspects of some embodiments are given. Inno way should the following examples be read to limit, or define, thescope of the invention.

EXAMPLES Example 1

The typical operating conditions for a multi-layer fixed-bed reactorwould be:

-   -   Catalysts used: Top layer—HZSM-5 (cracking catalyst);        -   2nd layer—Pt supported on mixed oxide (water-gas shift            catalyst);        -   3rd layer—NiMo and CoMo Supported on γ-alumina            (hydrotreating catalyst);        -   Bottom layer—Zeolite β (acid catalyst).    -   Pressure: Atmospheric    -   Temperature: 350-400° C.    -   Volume Ratio: Determined by space velocities required; also        considering cost, generally        -   Top layer:2nd layer:3rd layer:Bottom layer=5:2:3:10    -   Expected Bio-oil Quality:        -   Oxygen content: <10 wt %        -   Water content: <5 wt %        -   pH: 5-6

Example 2

The typical operating conditions for an acid catalyst fixed-bed reactorwould be:

-   -   Catalysts used: Zeolite β (acid catalyst).    -   Pressure: Atmospheric    -   Temperature: 350-400° C.    -   Expected Bio-oil Quality:        -   pH: 5-6

Example 3

The typical operating conditions for a multi-layer fixed-bed reactorwould be:

-   -   Catalysts used: Top layer—Pt supported on mixed oxide (water-gas        shift catalyst);        -   2nd layer-NiMo and CoMo Supported on γ-alumina            (hydrotreating catalyst);    -   Pressure: Atmospheric    -   Temperature: 350-400° C.    -   Expected Bio-oil Quality:        -   Oxygen content: <10 wt %        -   Water content: <5 wt %

Example 4

The typical operating conditions for a multi-layer fixed -bed reactorwould be:

-   -   Catalysts used: Top layer—HZSM-5 (cracking catalyst);        -   2nd layer—Pt supported on mixed oxide (water-gas shift            catalyst);        -   3rd layer-NiMo and CoMo Supported on y-alumina            (hydrotreating catalyst).    -   Pressure: Atmospheric    -   Temperature: 350-400° C.    -   Volume Ratio: Determined by space velocities required; also        considering cost, generally        -   Top layer:2nd layer:3rd layer=5:2:3    -   Expected Bio-oil Quality:        -   Oxygen content: <10 wt %        -   Water content: <5 wt %

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. While numerous changes may be made bythose skilled in the art, such changes are encompassed within the spiritof this invention as defined by the appended claims. Furthermore, nolimitations are intended to the details of construction or design hereinshown, other than as described in the claims below. It is thereforeevident that the particular illustrative embodiments disclosed above maybe altered or modified and all such variations are considered within thescope and spirit of the present invention. The terms in the claims havetheir plain, ordinary meaning unless otherwise explicitly and clearlydefined by the patentee.

What is claimed is:
 1. A process for the thermal conversion of biomasscomprising the steps of: a) thermal conversion of a biomass feedstock ina pyrolysis reactor; b) recovering a pyrolysis vapor from the reactor;c) passing the pyrolysis vapor in contact with a water-gas shiftreaction catalyst and a hydrotreating catalyst to produce an upgradedpyrolysis vapor; and d) converting the upgraded pyrolysis vapor fromstep c) into a liquid product.
 2. The process of claim 1, wherein thecatalysts in step c) are layered in a single reactor.
 3. The process ofclaim 2, wherein the catalysts are layered so that the pyrolysis vaporcontacts the water-gas shift reaction catalyst first and thehydrotreating catalyst second.
 4. The process of claim 2, wherein thereaction temperature is controlled for each catalyst layer in order topromote the corresponding reaction.
 5. The process of claim 4, whereinthe temperature is changed for each catalyst layer.
 6. The process ofclaim 1, wherein the water-gas shift reaction catalyst comprises atransaction metal or transaction metal oxide, and the hydrotreatingcatalyst comprises a noble metal catalyst, nickel molybdenum catalyst,or cobalt molybdenum catalyst.
 7. The process of claim 2, whereinhydrogen produced in the water-gas shift reaction is used with thehydrotreating catalyst.
 8. The process of claim 1, wherein the catalystsin step c) are contacted with the pyrolysis vapor in separate reactorsconnected in series.
 9. The process of claim 8, wherein the pyrolysisvapor contacts a guard bed before at least one of the reactors.
 10. Theprocess of claim 8, wherein the temperature and pressure is controlledfor each of the reactors.
 11. The process of claim 10, wherein at leastthe temperature is different for each reactor.
 12. The process of claim8, wherein hydrogen produced in the water-gas shift reactor is used inthe reactor with the hydrotreating catalyst.
 13. The process of claim 8,wherein the pyrolysis vapor contacts the water-gas shift reactioncatalyst first and the hydrotreating catalyst second.
 14. The process ofclaim 2, further comprising combining the liquid product directly withcrude oil to make a gasoline product.
 15. The process of claim 8,further comprising combining the liquid product directly with crude oilto make a gasoline product.